Smooth, adiabatically tapered, waveguide twists in thick-walled WR-650 have excellent return loss properties while remaining vacuum-capable (measured return losses less than -30 dB across the entire operating bandwidth). They also avoid the field enhancements and much of the resonant structure common to stepped waveguide twists. Please specify angular slope when requesting price quotation (nominal value of 6.3 degrees per inch).